JP2005075688A - Growing method for garnet-type single crystal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a growing method for a garnet-type single crystal whereby a large-sized grown crystal is yielded, the orientation control of the crystal is made possible, and the compositional difference in the crystal is not caused. <P>SOLUTION: In this growing method, a seed crystal is brought into contact with a melt which at least crystallizes X<SB>3</SB>Fe<SB>5</SB>O<SB>12</SB>[wherein X is Y (yttrium), (Bi, Re (provided Re is a rare earth element)), or (Bi Tb)]; then, while an X<SB>3</SB>Fe<SB>5</SB>O<SB>12</SB>single crystal is being grown by drawing up the seed crystal, a raw material having the same weight and composition as that of the above drawn-up single crystal is supplied to the melt. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a method for growing a garnet-type single crystal. Specifically, X ₃ Fe ₅ O ₁₂ [where X is Y (yttrium), (Bi, Re (where Re is a rare earth element)). Or (Bi, Tb). ] The growth method of the garnet-type single crystal represented by this.

  Conventionally, in the optical communication field, optical isolator elements and optical circulator elements have been widely used. The optical isolator element has a function of removing reflected return light that adversely affects the transmission characteristics of signal light. The optical circulator element is used in an optical add / drop device that extracts only signal light necessary for wavelength multiplexing communication or multiplexes new signal light.

As these optical isolator element and optical circulator element, a material having a Faraday effect which is a kind of magneto-optical effect is used. Specific examples of these materials include, for example, Y ₃ Fe ₅ O ₁₂ single crystal, (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal, and (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal. Y ₃ Fe ₅ O ₁₂ single crystal or the like is widely used as a magneto-optical material that can be used in a communication wavelength band of 1.3 to 1.6 μm.

Y ₃ Fe ₅ O ₁₂ single crystal are the materials that incongruent melting, in development of the _Y 3 _Fe 5 _{O 12} single crystal, by conventional pulling method (Czochralski _method), Y ₃ Fe _{5 O 12} A Y ₃ Fe ₅ O ₁₂ single crystal cannot be directly grown from a melt having a composition. For this reason, the growth of single crystals using flux has been performed. Further, although there is no clear phase diagram for (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal or (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal, it is considered that it cannot be grown directly by the pulling method. .

In the Y ₃ Fe ₅ O ₁₂ single crystal, bulk single crystal growth is the mainstream, and examples of the growth method include a flux annealing method, a TSFZ (Travelling Solvent Floating Zone) method, a solution pulling method, and the like. .

Flux slow cooling method, a _{Y 2 O 3, Fe 2 O} 3 other than the substances which are constituent elements of a single crystal as a flux, a method for growing a _Y 3 _Fe 5 _{O 12} single crystal by gradually cooling after melting.

The TSFZ method is a method obtained by partially improving the condensing heating type FZ method. This method uses a composition range in which the Fe component crystallized from the Y ₃ Fe ₅ O ₁₂ single crystal in the Y ₂ O ₃ —Fe ₂ O ₃ phase diagram is used as a solvent, and after the solvent component is melted Y ₃ Fe ₅ O ₁₂ is a method for growing a Y ₃ Fe ₅ O ₁₂ single crystal by using a sintered bar having a Y ₃ Fe ₅ O ₁₂ composition and using a seed crystal. As this seed crystal, a Y ₃ Fe ₅ O ₁₂ single crystal is used (see Patent Document 1).

The solution pulling _method, in Y _{2 O 3 -Fe 2} O 3 system phase _diagram, the Y ₃ Fe _{5 O 12} Fe component excessive melt the single crystal crystallizes _(Fe 2 _{O 3} range of 86~77mol%) In this method, a seed crystal is used to pull up a Y ₃ Fe ₅ O ₁₂ single crystal (see Patent Document 2).

JP 53-12800 A (Claim 1) JP 54-133481 A (Claim 1)

On the other hand, in (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal and (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal, the growth of the single crystal film is the mainstream, and the LPE (liquid phase epitaxial) method is applied. Has been. In addition to this, a method for growing a bulk single crystal by a flux slow cooling method and the like can be mentioned.

The LPE method uses a melt added with PbO, B ₂ O ₃ and excess Bi ₂ O ₃ as a flux in addition to the constituent elements of a single crystal, and after attaching a horizontally held single crystal substrate to the surface of the solution, This is a method for growing a single crystal film while rotating. As a method for growing this single crystal film, a method for growing a (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal (see Patent Document 3) or a method for growing a (Bi, Tb, Gd) ₃ Fe ₅ O ₁₂ single crystal. (See Patent Document 4).

JP 62-105931 A (Example 1) JP 63-35421 A (2nd page)

However, in the method of growing Y ₃ Fe ₅ O ₁₂ single crystal, (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal, and (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal, the following problems There is.

In the growth method of Y ₃ Fe ₅ O ₁₂ single crystal, when the flux slow cooling method is applied, since the Fe component constituting the Y ₃ Fe ₅ O ₁₂ single crystal and components other than Y are used as the flux, Y ₃ Fe ₅ O _When flux components other than the constituent elements of ₁₂ single crystals are mixed, there is a problem in that the optical quality is lowered because the crystal quality is lowered. In addition, this method has a problem that the orientation control of the growing single crystal cannot be performed.

In method for growing Y ₃ Fe ₅ O ₁₂ single crystal, in the case of applying the TSFZ method described in Patent Document _1, the Y _{2 O 3 -Fe 2} O 3 system phase _diagram, Y ₃ Fe _{5 O 12} single Since Y ₂ O ₃ —Fe ₂ O _{3 from} which the crystal is crystallized is used as a solvent, components other than the constituent elements are not mixed in, and the orientation of the grown crystal can be controlled. In general, there is a problem that the crystal diameter can be increased only to a diameter of about 10 mm.

In method for growing Y ₃ Fe ₅ O ₁₂ single crystal, even in the case of applying the solution pulling method described in Patent Document _2, the Y _{2 O 3 -Fe 2} O 3 system phase _diagram, Y ₃ Fe _{5 O 12} Since Y ₂ O ₃ —Fe ₂ O _{3 from} which a single crystal is crystallized is used as a solvent, components other than the constituent elements are not mixed, and the orientation of the grown crystal can be controlled. However, as the crystal growth progresses, the melt composition changes, so the temperature at which the crystals crystallize changes, and the amount of melt also decreases, making it difficult to control the crystal growth conditions. In addition, it is difficult to increase the size of the crystal because the crystal can be grown only up to the eutectic point. Furthermore, in the Y ₂ O ₃ —Fe ₂ O ₃ system phase diagram, there is also a report example that there is a solid solution region in the Y ₃ Fe ₅ O ₁₂ phase. In this case, a crystal that crystallizes as the crystal pulling growth proceeds. There is also a problem in that the composition changes and the composition shifts in the growth direction with the same crystal.

On the other hand, in the method of growing (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal and (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal, the LPE method described in Patent Document 3 or Patent Document 4 is applied. In order to grow a single crystal film, a single crystal substrate is used. As a material for this single crystal substrate, a (Gd, Ca) ₃ (Ga, Mg, Zr) ₅ O ₁₂ single crystal is mainly used, and the material for this single crystal substrate, the material for the single crystal film to be grown, It is necessary to match the lattice constants. Further, if there is a difference in thermal expansion coefficient between these materials, it causes cracks and warpage, resulting in deterioration of the quality of the single crystal film to be grown and reduction in yield at the time of device fabrication.

  Furthermore, there is a limit of about 500 to 600 μm in the film thickness from which a high quality single crystal film can be obtained. For this reason, it is not always possible to grow a single crystal film with a composition having excellent material characteristics, and the composition of the material of the single crystal film and the addition / substitution element are designed so as to satisfy the element characteristics below the limit film thickness. There is a need.

As described above, in the case of the LPE method, there are many restrictions on the composition selection of the single crystal material due to the manufacturing surface. In the melt used for the LPE method, PbO or B ₂ O ₃ is usually used as a flux in addition to the constituent elements of the single crystal. There is a possibility that such a flux component may be mixed into the single crystal film to be grown and cause characteristic deterioration.

In the growth method of (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal and (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal, when the flux annealing method is applied, similarly, the flux other than the constituent elements of the single crystal When the components are mixed, the crystal quality is deteriorated, so that there is a problem that optical characteristics are deteriorated. In addition, this method has a problem that the orientation control of the growing single crystal cannot be performed.

  The present invention provides a method for growing a garnet-type single crystal that eliminates such conventional problems, enables growth of a grown crystal and control of crystal orientation, and does not cause a deviation in crystal composition. The task is to do.

In order to solve the above-mentioned problem, the method for growing a garnet-type single crystal according to the present invention includes at least a melted X ₃ Fe ₅ O ₁₂ [where X is Y (yttrium), (Bi, Re (where Re is A rare earth element))) or (Bi, Tb). The seed crystal is brought into contact with the melt that crystallizes, and then the seed crystal is pulled up to grow an X ₃ Fe ₅ O ₁₂ single crystal, and has the same composition with the same weight as the pulled single crystal. A raw material is supplied to the melt.

In the method for growing a garnet-type single crystal of the present invention, in the method for growing a garnet-type single crystal, when X is Y (yttrium), the melt is Y ₂ O ₃ —Fe ₂ O _3. In the system phase diagram, it is preferable that Y ₃ Fe ₅ O ₁₂ is crystallized and has a composition of Fe ₂ O ₃ : Y ₂ O ₃ = 86 to 77 mol%: 14 to 23 mol%.

  In the garnet-type single crystal growth method of the present invention, when X is Y (yttrium), the melt is melted in a crucible, and the crucible is provided in an external crucible and in the external crucible. The inner crucible is preferably provided with an outer crucible and a flow passage through which the melt in the inner crucible flows.

In the method for growing a garnet-type single crystal according to the present invention, when X is Y (yttrium), the seed crystal is a Y ₃ Fe ₅ O ₁₂ single crystal and / or a Gd ₃ Ga ₅ O ₁₂ single crystal. It is preferable that

Further, in the method for growing a garnet-type single crystal of the present invention, when X is (Bi, Re (where Re is a rare earth element)), at least (Bi, The seed crystal is brought into contact with the melt for crystallizing Re) ₃ Fe ₅ O _12, and then the seed crystal is pulled up to grow the (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal while growing the single crystal. A raw material having the same weight as the crystal and having the same composition is supplied to the melt.

  In the method for growing a garnet-type single crystal of the present invention, when X is (Bi, Re (where Re is a rare earth element)), the melt is melted in a crucible, The crucible preferably includes an external crucible, an internal crucible provided in the external crucible, and a flow passage for allowing the external crucible and the melt in the internal crucible to flow therethrough.

In the method for growing a garnet-type single crystal of the present invention, when X is (Bi, Re (where Re is a rare earth element)), the seed crystal is (Bi, Re) _3. Fe ₅ O ₁₂ single crystal and / or (Gd, Ca) ₃ (Ga, Mg, Zr) ₅ O ₁₂ single crystal are preferable.

Furthermore, in the method for growing a garnet-type single crystal according to the present invention, when X is (Bi, Tb) in the method for growing a garnet-type single crystal, at least (Bi, Tb) melted in a crucible. After bringing the seed crystal into contact with the melt that crystallizes ₃ Fe ₅ O ₁₂ , the seed crystal is pulled up (Bi, Tb) while growing the ₃ Fe ₅ O ₁₂ single crystal, A raw material having the same composition and having the same weight is supplied to the melt.

  In the method for growing a garnet-type single crystal according to the present invention, when X is (Bi, Tb), the melt is melted in a crucible, and the crucible is placed in an external crucible and in the external crucible. It is preferable to include an inner crucible provided and a flow passage through which the outer crucible and the melt in the inner crucible flow.

In the method for growing a garnet-type single crystal of the present invention, when X is (Bi, Tb), the seed crystal is a (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal and / or (Gd, Ca) ₃ (Ga, Mg, Zr) ₅ O ₁₂ single crystal is preferable.

  According to the present invention, it is possible to provide a method for growing a garnet-type single crystal that can increase the size of a grown crystal, control the orientation of the crystal, and does not cause a crystal composition shift.

[First Embodiment]
The method for growing a garnet-type single crystal according to the first embodiment of the present invention, that is, X ₃ Fe ₅ O ₁₂ [where X is Y (yttrium), (Bi, Re (where Re is a rare earth element). )) Or (Bi, Tb). ] Is a case where X is Y (yttrium), that is, a method for growing a Y ₃ Fe ₅ O ₁₂ single crystal.

The raw material supply pulling apparatus 1 used in the method for growing a Y ₃ Fe ₅ O ₁₂ single crystal according to the first embodiment will be described. As shown in FIG. 1, the raw material supply pulling apparatus 1 includes a chamber 2, a weight detection unit 3 installed in the upper part of the chamber 2, a raw material supply apparatus 4 installed in the upper part of the chamber 2, and an automatic raw material. A supply control unit 5; a refractory 6 provided inside the chamber 2; a heater 7 provided on the side of the refractory 6; a crucible 8 provided in the refractory 6; And a crucible rotating portion 9 provided below the crucible 8.

Weight detecting unit 3, to measure the weight of the resulting Y ₃ Fe ₅ O ₁₂ single crystal, as long as it has sufficient accuracy. A pulling rod 3A is provided below the weight detection unit 3. The base end of the pulling rod 3A is connected to the weight detection unit 3, and the tip of the pulling rod 3A is a portion to which the seed crystal is attached. The weight detection unit 3 further has a function of pulling up the seed crystal while rotating the pulling rod 3A when pulling up the seed crystal.

  The raw material supply device 4 stores a predetermined single crystal raw material and supplies it to the crucible 8. The automatic raw material supply control unit 5 controls the weight detection unit 3 so that the raw material supply device 4 supplies the same weight as the weight of the single crystal to be pulled up. In addition, the raw material in this invention is a raw material supplied in order to hold | maintain a composition of a melt.

  The heater 7 only needs to have a function of keeping the temperature at the time of growing the single crystal at a predetermined temperature.

  Examples of the material for the crucible 8 include platinum, platinum-rhodium, iridium, molybdenum, tungsten, fused quartz, and carbon. The crucible 8 includes an external crucible 8A, an internal crucible 8B provided in the external crucible 8A, and a flow passage 8C for circulating the melt in the external crucible 8A and the internal crucible 8B.

  A known crucible may be used as the crucible 8.

  In the present embodiment, the outer crucible 8A and the inner crucible 8B are cylindrical. The raw material supplied later is supplied to the space formed by the outer crucible 8A and the inner crucible 8B.

  The flow path 8C may be, for example, a through-hole formed in the side wall surface of the internal crucible 8B, or a cut formed in the side wall surface on the bottom side of the internal crucible 8B.

  The crucible rotating section 9 only needs to have a drive device (not shown) that supports the crucible 8 from below and rotates the crucible 8 at a predetermined rotational speed.

In the method for growing a Y ₃ Fe ₅ O ₁₂ single crystal according to the first embodiment of the present invention, after bringing a seed crystal into contact with a melt that crystallizes at least Y ₃ Fe ₅ O ₁₂ melted in a crucible, In this method, the seed crystal is pulled up to grow a Y ₃ Fe ₅ O ₁₂ single crystal, and a raw material having the same composition and weight as the pulled crystal is supplied to the melt.

[Production of melt]
Here, the crucible 8 is used as the crucible. For the production of the melt, Fe ₂ O ₃ and Y ₂ O ₃ are used, weighed and mixed, and then molded. The molding methods include casting molding method, extrusion molding method, injection molding method, die press molding method, rubber press molding method (sometimes abbreviated as CIP method), cyclic CIP method, doctor blade method, calendar roll. Law.

  The molded body is filled in the outer crucible 8A and the inner crucible 8B. And it heats with the heater-7 and fuse | melts the molded object with which it filled, and obtains a melt.

In the method for growing a _Y 3 _Fe 5 _{O 12} single crystal of the present invention, the melt, the _Y 2 _{O 3 -Fe} 2 _O 3 system phase diagram as shown in FIG. _2, Y ₃ Fe _{5 O 12} is It is preferable to have a composition of crystallizing Fe ₂ O ₃ : Y ₂ O ₃ = 86 to 77 mol%: 14 to 23 mol%.

[Production of raw materials to be supplied]
On the other hand, Fe ₂ O ₃ and Y ₂ O ₃ are used for production of the raw material to be supplied, and after molding and mixing, molding is performed. The molding methods include casting molding method, extrusion molding method, injection molding method, die press molding method, rubber press molding method (sometimes abbreviated as CIP method), cyclic CIP method, doctor blade method, calendar roll. Law.

The molded body is heat-treated at 1300-1400 ° C. to obtain a Y ₃ Fe ₅ O ₁₂ sintered body. Here, as sintering methods, atmosphere sintering method, reaction sintering method, thermal plasma sintering method, electric heating sintering method, multiaxial electric heating sintering method, discharge plasma sintering method, hot isothermal method, etc. And pressure sintering method (Hot Isostatic Pressing; sometimes abbreviated as HIP method).

The Y ₃ Fe ₅ O ₁₂ sintered body is pulverized and classified to 180 to 500 μm, and used as a raw material supplied from the raw material supply device 4. Here, examples of the pulverizing means include a ball mill, a stirring mill, a shear mill, and a colloid mill.

[Seed crystals to be used]
In the method for growing a Y ₃ Fe ₅ O ₁₂ single crystal of the present invention, the seed crystal is preferably a Y ₃ Fe ₅ O ₁₂ single crystal and / or a Gd ₃ Ga ₅ O ₁₂ single crystal, (111) More preferably, it is a Y ₃ Fe ₅ O ₁₂ single crystal and / or a Gd ₃ Ga ₅ O ₁₂ single crystal of orientation.
The size of the seed crystal is, for example, 3 to 5 mm square.

[Pulling growth of Y ₃ Fe ₅ O ₁₂ single crystal]
While the crucible 8 is rotated by the crucible rotating part 9, the melt is heated by the heater 7 to melt the melt. After melting the melt, the seed crystal previously attached to the tip of the pulling rod 3A is immersed in the melt in the internal crucible 8B at a temperature at which the melt is stable within a predetermined temperature of 1420 to 1450 ° C. At this time, while rotating the seed crystal, the seed crystal is lowered to the crucible 8, and the crucible 8 is rotated in the direction opposite to the rotation direction of the seed crystal. Thereafter, the Y ₃ Fe ₅ O ₁₂ single crystal is grown by moving the seed crystal upward while rotating the seed crystal.

Note that the atmosphere for growing the Y ₃ Fe ₅ O ₁₂ single crystal was adjusted to an air atmosphere by adjusting the chamber 2.

[Supply material supply]
The supply of the raw material may be performed, for example, when the straight body portion of the grown crystal is formed. During the crystal growth, the weight change of the grown crystal is constantly monitored by the weight detector 3, for example, an electronic balance. Then, a feedstock having a composition of Y ₃ Fe ₅ O ₁₂ corresponding to the weight increase of the grown crystal is supplied from the raw material supply device 4. As for the supply of the feedstock, a feedstock having a Y ₃ Fe ₅ O ₁₂ composition may be continuously fed. If the composition of the melt does not change, the weight of the grown crystal is increased with a certain time interval. feed min Y ₃ Fe ₅ O ₁₂ composition corresponding to the increase may be supplied to.

The raw material supply device 4 is provided with a supply pipe 4A made of alumina, and a supply raw material having a composition of Y ₃ Fe ₅ O ₁₂ is supplied between the external crucible 8A and the internal crucible 8B through the supply pipe 4A. In order to smoothly supply this raw material, nitrogen gas or air is allowed to flow at 150 to 300 mL / min in the supply pipe 4A. By the above procedure, a Y ₃ Fe ₅ O ₁₂ single crystal is grown.

The first embodiment as described above has the following effects.
(1-1) A melt produced with the progress of crystal growth by supplying a raw material having a Y ₃ Fe ₅ O ₁₂ composition having the same weight as that of the pulled Y ₃ Fe ₅ O ₁₂ single crystal to the melt. A change in composition and a decrease in the amount of melt are prevented and kept constant. Since the growth melt composition is kept constant, the crystal composition to be crystallized is also constant. For this reason, even when there is a solid solution region in the Y ₃ Fe ₅ O ₁₂ phase, there is no composition shift in the growth direction in the same crystal, so a Y ₃ Fe ₅ O ₁₂ single crystal with high composition uniformity is obtained. Can be obtained. Moreover, the method for growing a single crystal according to the present invention is usually performed except that a raw material having a Y ₃ Fe ₅ O ₁₂ composition having the same weight as that of the obtained Y ₃ Fe ₅ O ₁₂ single crystal is supplied to the melt. Therefore, the growth crystal can be enlarged and the crystal orientation can be controlled.

(1-2) The melt is Fe ₂ O ₃ : Y ₂ O ₃ where Y ₃ Fe ₅ O ₁₂ crystallizes in the Y ₂ O ₃ —Fe ₂ O ₃ phase diagram as shown in FIG. = 86 to 77 mol%: By having a composition of 14 to 23 mol%, elements other than the constituent elements of the Y ₃ Fe ₅ O ₁₂ single crystal are not mixed in, so that deterioration of the crystal quality can be prevented.

(1-3) The crucible 8 includes an external crucible 8A, an internal crucible 8B, and a flow passage 8C. The single crystal is grown inside the inner crucible 8B, and the raw material is supplied to the melt between the outer crucible 8A and the inner crucible 8B. Since the melt surface is blocked by the internal crucible 8B, the supplied raw material does not reach the crystal growth portion without being melted, and the crystal quality can be prevented from being lowered. The supplied raw material is melted between the outer crucible 8A and the inner crucible 8B. The melt between the outer crucible 8A and the inner crucible 8B and the melt in the inner crucible 8B can be mixed via the flow passage 8C, and prevent composition deviation (composition segregation) in the melt. Can do.

(1-4) Since the seed crystal is a Y ₃ Fe ₅ O ₁₂ single crystal and / or a Gd ₃ Ga ₅ O ₁₂ single crystal, the lattice constant of the Y ₃ Fe ₅ O ₁₂ single crystal is the same. Thus, the lattice constant of the obtained Y ₃ Fe ₅ O ₁₂ single crystal can be matched.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the following description, the same parts and members as those already described are denoted by the same reference numerals and description thereof is simplified. A method for growing a garnet-type single crystal according to the second embodiment, that is, X ₃ Fe ₅ O ₁₂ (where X is Y (yttrium), (Bi, Re (where Re is a rare earth element))), Or (Bi, Tb). ] Is a case where X is (Bi, Re (where Re is a rare earth element))), that is, a method for growing a (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal. .

Since according to the second embodiment _{(Bi, Re) 3 Fe 5} O 12 material supply pulling apparatus used in the method for growing a single crystal is the same as the raw material supply pulling apparatus 1 according to the first embodiment The description is omitted.

Second according to the embodiment _{(Bi, Re) 3} method for growing a Fe _{5 O 12} single crystal of the present _{invention, (Bi, Re) 3 Fe} 5 O 12 single crystal (Re is a rare earth element.) (( Bi, Re) ₃ Fe ₅ O ₁₂ is Bi _3−z Re _z Fe ₅ O ₁₂ and 0 <Z <3), and is a growing method of at least (Bi, Re) in a crucible. ) After bringing the seed crystal into contact with the melt for crystallizing ₃ Fe ₅ O ₁₂ , the seed crystal is pulled up to grow the (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal, and the same as the pulled crystal This is a method of supplying a raw material having the same composition to the melt by weight.

[Production of melt]
Here, the crucible 8 is used as the crucible. For producing the melt, Bi ₂ O _3, Fe ₂ O ₃ and Re ₂ O ₃ (or Re ₄ O ₇ ) are used, weighed and mixed, and then molded. The molding methods include casting molding method, extrusion molding method, injection molding method, die press molding method, rubber press molding method (sometimes abbreviated as CIP method), cyclic CIP method, doctor blade method, calendar roll. Law.

  The molded body is filled in the outer crucible 8A and the inner crucible 8B. And the filled molded object is heated with the heater-7, the filled molded object is fuse | melted, and a melt is obtained.

[Production of raw materials to be supplied]
On the other hand, Bi ₂ O _3, Fe ₂ O ₃ , and Re ₂ O ₃ (or Re ₄ O ₇ ) are used for production of the raw material to be supplied, and after molding and mixing, molding is performed. The molding methods include casting molding method, extrusion molding method, injection molding method, die press molding method, rubber press molding method (sometimes abbreviated as CIP method), cyclic CIP method, doctor blade method, calendar roll. Law.

The compact is heat treated at 1000 to 1400 ° C. to obtain a (Bi, Re) ₃ Fe ₅ O ₁₂ sintered body. Here, as sintering methods, atmosphere sintering method, reaction sintering method, thermal plasma sintering method, electric heating sintering method, multiaxial electric heating sintering method, discharge plasma sintering method, hot isothermal method, etc. And pressure sintering method (Hot Isostatic Pressing; sometimes abbreviated as HIP method).

This (Bi, Re) ₃ Fe ₅ O ₁₂ sintered body is pulverized and classified to 180 to 500 μm, and used as a feedstock supplied from the feedstock supply device 4. Here, examples of the pulverizing means include a ball mill, a stirring mill, a shear mill, and a colloid mill.

[Seed crystals to be used]
In the method for growing a (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal of the present invention, the seed crystal is a (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal and / or (Gd, Ca) ₃ (Ga, Mg, Zr) ₅ O ₁₂ single crystal is preferable, (111) -oriented (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal and / or (Gd, Ca) ₃ (Ga, Mg, Zr) ₅ O More preferably, it is ₁₂ single crystals.
The size of the seed crystal is, for example, 3 to 5 mm square.

[Pulling growth of (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal]
While the crucible 8 is rotated by the crucible rotating unit 9, the melt is heated by the heater 7 to melt the melt. After melting the melt, the seed crystal previously attached to the tip of the pulling bar 3A is immersed in the melt in the internal crucible 8B at a temperature at which the melt is stable within a predetermined temperature of 1100 to 1300 ° C. At this time, while rotating the seed crystal, the seed crystal is lowered to the crucible 8, and the crucible 8 is rotated in the direction opposite to the rotation direction of the seed crystal. Thereafter, the (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal is grown by moving the seed crystal upward while rotating the seed crystal.

Note that the atmosphere for growing the (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal was an air atmosphere by adjusting the chamber 2.

[Supply material supply]
The supply of the raw material may be performed, for example, when the straight body portion of the grown crystal is formed. During the crystal growth, the weight change of the grown crystal is constantly monitored by the weight detector 3, for example, an electronic balance. Then, a (Bi, Re) ₃ Fe ₅ O ₁₂ supply raw material having the same composition as that of the growth crystal corresponding to the weight increase of the growth crystal is supplied from the raw material supply device 4. As for the supply of the feedstock, the (Bi, Re) ₃ Fe ₅ O ₁₂ feedstock may be continuously fed, and if the composition of the melt does not change, the grown crystal is grown at a certain time interval. (Bi, Re) ₃ Fe ₅ O ₁₂ feedstock may be supplied in an amount corresponding to an increase in weight.

The raw material supply device 4 is provided with a supply pipe 4A made of alumina, and the (Bi, Re) ₃ Fe ₅ O ₁₂ supply raw material having the same composition as the grown crystal is supplied to the external crucible 8A and the internal through the supply pipe 4A. Supply between crucible 8B. In order to smoothly supply this raw material, nitrogen gas or air is allowed to flow at 150 to 300 mL / min in the supply pipe 4A. The (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal is grown by the above procedure.

According to the second embodiment as described above, there are the following effects.
(2-1) Melt composition produced with the progress of crystal growth by supplying a raw material having the same composition as the weight of the pulled (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal to the melt. Change and decrease in the melt amount are prevented and kept constant. Since the growth melt composition is kept constant, the crystal composition to be crystallized is also constant. As a result, even when a solid solution region exists in the (Bi, Re) ₃ Fe ₅ O ₁₂ phase, composition deviation does not occur in the growth direction in the same crystal, so that (Bi, Re) ₃ Fe ₅ O with high composition uniformity is obtained. ₁₂ single crystals can be obtained. In addition, the method for growing a single crystal according to the present invention is the same as that of the obtained (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal except that a raw material having the same composition and weight is supplied to the melt. Since it is the same as the pulling method, it is possible to increase the size of the grown crystal and control the crystal orientation.

(2-2) The crucible 8 includes an external crucible 8A, an internal crucible 8B, and a flow passage 8C. The single crystal is grown inside the inner crucible 8B, and the raw material is supplied to the melt between the outer crucible 8A and the inner crucible 8B. Since the melt surface is blocked by the internal crucible 8B, the supplied raw material does not reach the crystal growth portion without being melted, and the crystal quality can be prevented from being lowered. The supplied raw material is melted between the outer crucible 8A and the inner crucible 8B. The melt between the outer crucible 8A and the inner crucible 8B and the melt in the inner crucible 8B can be mixed via the flow passage 8C, and prevent composition deviation (composition segregation) in the melt. Can do.

(2-3) The seed crystal is a (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal and / or a (Gd, Ca) ₃ (Ga, Mg, Zr) ₅ O ₁₂ single crystal, , Re) ₃ Fe ₅ O ₁₂ single crystal has the same lattice constant, so that the lattice constant of the obtained (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal can be matched.

(2-4) As in the case of the conventional LPE method, there is no limitation on the crystal thickness at which a high-quality single crystal can be obtained, so that restrictions on the crystal composition and additive elements can be reduced.

[Third Embodiment]
A method for growing a garnet-type single crystal according to a third embodiment of the present invention, that is, X ₃ Fe ₅ O ₁₂ [where X is Y (yttrium), (Bi, Re (where Re is a rare earth element). )) Or (Bi, Tb). ] Is a case where X is (Bi, Tb), that is, a method for growing a (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal.

Since the raw material supply pulling apparatus used in the method for growing the (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal according to the third embodiment is the same as the raw material supply pulling apparatus 1 according to the first embodiment, The description is omitted.

Third according to embodiment _{(Bi, Tb) 3} method for growing a Fe _{5 O 12} single crystal of the present _{invention, (Bi, Tb) 3 Fe} 5 O 12 single crystal _{((Bi, Tb) 3 Fe} 5 O 12 is , Bi _3-z Tb _z Fe ₅ O ₁₂ and 0 <Z <3), and crystallizes at least (Bi, Tb) ₃ Fe ₅ O ₁₂ melted in the crucible. After bringing the seed crystal into contact with the melt, pulling up the seed crystal to grow a (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal, the raw material having the same composition with the same weight as the pulled crystal is It is a method of supplying to the melt.

[Production of melt]
Here, the crucible 8 is used as the crucible. For production of the melt, Tb ₄ O _7, Bi ₂ O _{3 and} Fe ₂ O ₃ are used, weighed and mixed, and then molded. The molding methods include casting molding method, extrusion molding method, injection molding method, die press molding method, rubber press molding method (sometimes abbreviated as CIP method), cyclic CIP method, doctor blade method, calendar roll. Law.

  The molded body is filled in the outer crucible 8A and the inner crucible 8B. And the filled molded object is heated with the heater-7, the filled molded object is fuse | melted, and a melt is obtained.

[Production of raw materials to be supplied]
On the other hand, Tb ₄ O _7, Bi ₂ O _{3, and} Fe ₂ O ₃ are used to produce the raw material to be supplied, and after molding and mixing, molding is performed. The molding methods include casting molding method, extrusion molding method, injection molding method, die press molding method, rubber press molding method (sometimes abbreviated as CIP method), cyclic CIP method, doctor blade method, calendar roll. Law.

The compact is heat treated at 1000 to 1100 ° C. to obtain a (Bi, Tb) ₃ Fe ₅ O ₁₂ sintered body. Here, as sintering methods, atmosphere sintering method, reaction sintering method, thermal plasma sintering method, electric heating sintering method, multiaxial electric heating sintering method, discharge plasma sintering method, hot isothermal method, etc. And pressure sintering method (Hot Isostatic Pressing; sometimes abbreviated as HIP method).

This (Bi, Tb) ₃ Fe ₅ O ₁₂ sintered body is pulverized and classified to 180 to 500 μm, and used as a feedstock supplied from the feedstock supply device 4. Here, examples of the pulverizing means include a ball mill, a stirring mill, a shear mill, and a colloid mill.

[Seed crystals to be used]
In the method of growing a (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal of the present invention, the seed crystal is a (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal and / or (Gd, Ca) ₃ (Ga, Mg, Zr) ₅ O ₁₂ single crystal is preferable, and (111) -oriented (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal and / or (Gd, Ca) ₃ (Ga, Mg, Zr) ₅ O More preferably, it is ₁₂ single crystals.

[Pulling growth of (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal]
While the crucible 8 is rotated by the crucible rotating part 9, the melt is heated by the heater 7 to melt the melt. After melting the melt, the seed crystal previously attached to the tip of the pulling rod 3A is immersed in the melt in the internal crucible 8B at a temperature at which the melt is stable within a predetermined temperature of 1150 to 1250 ° C. At this time, while rotating the seed crystal, the seed crystal is lowered to the crucible 8, and the crucible 8 is rotated in the direction opposite to the rotation direction of the seed crystal. Thereafter, the (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal is grown by moving the seed crystal upward while rotating the seed crystal.

Note that the atmosphere for growing the (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal was adjusted to an air atmosphere by adjusting the chamber 2.

[Supply material supply]
The supply of the raw material may be performed, for example, when the straight body portion of the grown crystal is formed. During the crystal growth, the weight change of the grown crystal is constantly monitored by the weight detector 3, for example, an electronic balance. Then, a (Bi, Tb) ₃ Fe ₅ O ₁₂ feedstock having the same composition as that of the growth crystal corresponding to the weight increase of the growth crystal is supplied from the raw material supply device 4. Regarding the supply of the feedstock, the (Bi, Tb) ₃ Fe ₅ O ₁₂ feedstock may be fed continuously, and if the composition of the melt does not change, the grown crystal is grown at a certain time interval. (Bi, Tb) ₃ Fe ₅ O ₁₂ feedstock may be supplied corresponding to the weight increase.

The material supply device 4, an alumina supply pipe 4A is provided, inside and through this supply pipe 4A is the same composition as the growing crystal _{(Bi, Tb) 3 Fe 5} O 12 feed an external crucible 8A Supply between crucible 8B. In order to smoothly supply this raw material, nitrogen gas or air is allowed to flow at 150 to 300 mL / min in the supply pipe 4A. By the above procedure, a (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal is grown.

The third embodiment as described above has the following effects.
(3-1) Melt composition produced with the progress of crystal growth by supplying a raw material having the same composition as the weight of the pulled (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal to the melt. Change and decrease in the melt amount are prevented and kept constant. Since the growth melt composition is kept constant, the crystal composition to be crystallized is also constant. Thereby, even when (Bi, Tb) ₃ Fe ₅ O ₁₂ has a solid solution region, composition deviation does not occur in the growth direction in the same crystal, and thus (Bi, Tb) ₃ Fe ₅ O _{12 has} high composition uniformity. A single crystal can be obtained. In addition, the method for growing a single crystal according to the present invention is a normal method except that a raw material having the same composition as the weight of the obtained (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal is supplied to the melt. Since it is the same as the pulling method, it is possible to increase the size of the grown crystal and control the crystal orientation.

(3-2) The crucible 8 includes an external crucible 8A, an internal crucible 8B, and a flow passage 8C. The single crystal is grown inside the inner crucible 8B, and the raw material is supplied to the melt between the outer crucible 8A and the inner crucible 8B. Since the melt surface is blocked by the internal crucible 8B, the supplied raw material does not reach the crystal growth portion without being melted, and the crystal quality can be prevented from being lowered. The supplied raw material is melted between the outer crucible 8A and the inner crucible 8B. The melt between the outer crucible 8A and the inner crucible 8B and the melt in the inner crucible 8B can be mixed via the flow passage 8C, and prevent composition deviation (composition segregation) in the melt. Can do.

The (3-3) seed crystal is a (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal and / or a (Gd, Ca) ₃ (Ga, Mg, Zr) ₅ O ₁₂ single crystal. Since the lattice constant of Tb) ₃ Fe ₅ O ₁₂ single crystal is the same, the lattice constant of the obtained (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal can be matched.

(3-4) As in the case of the conventional LPE method, there is no limitation on the crystal thickness at which a high-quality single crystal can be obtained, so that restrictions on the crystal composition and additive elements can be reduced.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In addition, this invention is not limited to the content of the Example.

[Example 1]
The Y ₃ Fe ₅ O ₁₂ single crystal was grown according to the Y ₃ Fe ₅ O ₁₂ single crystal growth method of the first embodiment. Specific conditions are as follows.

Specific conditions used in the above-mentioned [Preparation of melt] Powder: Commercially available powder of 99.99% purity Fe ₂ O ₃ and Y ₂ O ₃ Fe ₂ O ₃ and Y ₂ O ₃ Composition: Fe ₂ O ₃ : Y ₂ O ₃ = 84 mol%: 16 mol%
Molding method of these mixed powders: CIP method external crucible 8A: platinum, inner diameter 120 mm
Internal crucible 8B: made of platinum, inner diameter 80mm

The specific conditions used powder during Preparation of raw material supplied: composition of the powder _Fe 2 _{O 3} and _Y 2 _{O 3} having a purity of 99.99% _Fe 2 _{O 3} and _Y 2 _{O 3,} which is commercially available: Fe ₂ O ₃ : Y ₂ O ₃ = 62.5 mol%: 37.5 mol%
Molding method of these mixed powders: CIP method (1 ton / cm ² pressure condition)

Specific conditions in the above [Seed crystal to be used] Seed crystal to be used: (111) -oriented Y ₃ Fe ₅ O ₁₂ single crystal and Gd ₃ Ga ₅ O ₁₂ single crystal

Specific conditions in the above [Y ₃ Fe ₅ O ₁₂ single crystal pulling growth] Heating method: High-frequency heating atmosphere: Temperature at which the atmospheric melt is stable: 1430 ° C.
Seed crystal rotation speed: 4 rpm
Seed crystal pulling speed: 0.2 mm / h
Rotating speed of crucible 8: 6rpm

Specific conditions at the time of the above [supply of feedstock] Flow rate of gas flowing in the supply pipe 4A: 300 mL / min

[Example 2]
According to the method for growing a (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal of the second embodiment, a (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal was grown. Tb was selected as the rare earth element.

Specific conditions used in the above-mentioned [Preparation of melt] Powder: Commercially available powder of 99.99% purity Bi ₂ O ₃ and Fe ₂ O ₃ , Tb ₄ O ₇ (Bi, Re) ₃ Fe ₅ Composition of O ₁₂ : Tb: Bi: Fe = 15: 35: 50 (mol%)
Molding method of these mixed powders: CIP method external crucible 8A: platinum, inner diameter 120 mm
Internal crucible 8B: made of platinum, inner diameter 80mm

Specific conditions used in the above [Production of raw materials to be supplied]: Commercially available powders of 99.99% pure Bi ₂ O _3, Fe ₂ O ₃ and Tb ₄ O ₇
Composition of (Bi, Re) ₃ Fe ₅ O ₁₂ : Bi _0.5 Tb _2.5 Fe ₅ O ₁₂
Molding method of these mixed powders: CIP method (1 ton / cm ² pressure condition)

Specific conditions for the above [Seed crystal to be used] Seed crystal to be used: (111) -oriented (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal and (Gd, Ca) ₃ (Ga, Mg, Zr) ₅ O ₁₂ single crystal

Specific conditions for the above-mentioned [(Bi, Re) ₃ Fe ₅ O ₁₂ single crystal pulling growth] Heating method: High-frequency heating atmosphere: Temperature at which the atmospheric melt is stable: 1230 ° C.
Seed crystal rotation speed: 4 rpm
Seed crystal pulling speed: 0.2 mm / h
Rotating speed of crucible 8: 6rpm

Specific conditions at the time of the above [supply of feedstock] Flow rate of gas flowing in the supply pipe 4A: 300 mL / min

[Example 3]
The (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal was grown according to the method for growing the (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal of the third embodiment.

Specific conditions used in the above-mentioned [Preparation of melt] Powder: Tb ₄ O ₇ and Bi ₂ O _3, Fe ₂ O ₃ powder (Bi, Tb) ₃ Fe ₅ with a purity of 99.99% on the market Composition of O ₁₂ : Tb: Bi: Fe = 15: 35: 50 (mol%)
Molding method of these mixed powders: CIP method external crucible 8A: platinum, inner diameter 120 mm
Internal crucible 8B: made of platinum, inner diameter 80mm

Specific conditions used in the above-mentioned [Preparation of raw material to be supplied] Powder: Tb ₄ O ₇ and Bi ₂ O _{3 and} Fe ₂ O ₃ powder (Bi, Tb) ₃ Fe with a purity of 99.99% Composition of ₅ O ₁₂ : Bi _0.5 Tb _2.5 Fe ₅ O ₁₂
Molding method of these mixed powders: CIP method (1 ton / cm ² pressure condition)

Specific Conditions for the above [Used Seed Crystal] Used Seed Crystal: (111) Oriented (Bi, Tb) ₃ Fe ₅ O ₁₂ Single Crystal and (Gd, Ca) ₃ (Ga, Mg, Zr) ₅ O ₁₂ single crystal

Specific conditions for the above-described [(Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal pulling growth] Heating method: High-frequency heating atmosphere: Temperature at which the atmospheric melt is stable: 1230 ° C.
Seed crystal rotation speed: 4 rpm
Seed crystal pulling speed: 0.2 mm / h
Rotating speed of crucible 8: 6rpm

Specific conditions at the time of the above [supply of feedstock] Flow rate of gas flowing in the supply pipe 4A: 300 mL / min

[Evaluation methods and results]
It was confirmed whether the predetermined single crystal was grown using the single crystal obtained in each Example. As an evaluation method, X-ray Laue method, X-ray diffraction method (XRD measurement), and chemical analysis were adopted.

It was confirmed that the Y ₃ Fe ₅ O ₁₂ single crystal obtained in Example 1 was a single crystal by the X-ray Laue method. Moreover, it was confirmed by the above X-ray diffraction method (XRD measurement) that it was Y ₃ Fe ₅ O ₁₂ single phase. From these, it was confirmed that a Y ₃ Fe ₅ O ₁₂ single crystal was obtained.

Moreover, it was confirmed by chemical analysis that the (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal obtained in Example 2 was Bi _0.5 Tb _2.5 Fe ₅ O ₁₂ .

Furthermore, the (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal obtained in Example 3 shows the same peak pattern as the Y ₃ Fe ₅ O ₁₂ phase by the X-ray diffraction method (XRD measurement). It was. This confirmed that the grown crystal was a garnet phase. Moreover, the peak position was shifted to a lower angle side than the Y ₃ Fe ₅ O ₁₂ phase, and it was confirmed that the grown crystal had a larger lattice constant than Y ₃ Fe ₅ O ₁₂ . . Furthermore, it was confirmed by chemical analysis that a (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal (Bi _0.5 Tb _2.5 Fe ₅ O ₁₂ single crystal) having no compositional deviation was obtained.

  The present invention is not limited to the above examples. For example, the melt used for growth is composed of only the constituent element components of the target single crystal material, and the target crystal phase is crystallized. In addition to the melt to be melted, the melt may contain a flux component other than the constituent elements of the target single crystal material and crystallize the target crystal phase.

The method for growing a garnet-type single crystal according to the present invention includes a method for growing a Y ₃ Fe ₅ O ₁₂ single crystal, a method for growing a (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal, and (Bi, Tb) ₃ Fe ₅ O _12. Used in single crystal growth methods and the like.

FIG. 1 is a schematic view of a raw material supply pulling apparatus used in the method for growing a garnet type single crystal according to the present invention. FIG. 2 is a Y ₂ O ₃ —Fe ₂ O ₃ phase diagram.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Raw material supply pull-up apparatus 2 Chamber 3 Weight detection part 4 Raw material supply apparatus 5 Automatic raw material supply control part 6 Refractory 7 Heater
8 Crucible 9 Crucible rotating part 4A Supply pipe 8A External crucible 8B Internal crucible 8C Flow path

Claims (10)

Molten at least X ₃ Fe ₅ O ₁₂ (where X is Y (yttrium), (Bi, Re (where Re is a rare earth element))), or (Bi, Tb). In the melt that crystallizes
After contacting the seed crystal,
While pulling up the seed crystal and growing an X ₃ Fe ₅ O ₁₂ single crystal,
A method for growing a garnet-type single crystal, characterized in that a raw material having the same composition as the pulled single crystal is supplied to the melt. In the method for growing a garnet-type single crystal according to claim 1,
X is Y (yttrium),
In the Y ₂ O ₃ —Fe ₂ O ₃ phase diagram, the melt is
_2. The garnet-type single crystal according to claim 1, wherein Y ₃ Fe ₅ O ₁₂ is crystallized and has a composition of Fe ₂ O ₃ : Y ₂ O ₃ = 86 to 77 mol%: 14 to 23 mol%. Training method. The melt is melted in a crucible, the crucible is an external crucible,
An internal crucible provided in the external crucible;
The method for growing a garnet-type single crystal according to claim 2, further comprising a flow passage for circulating the melt in the outer crucible and the inner crucible. 4. The method for growing a garnet-type single crystal according to claim 2, wherein the seed crystal is a Y ₃ Fe ₅ O ₁₂ single crystal and / or a Gd ₃ Ga ₅ O ₁₂ single crystal. In the method for growing a garnet-type single crystal according to claim 1,
X is (Bi, Re (where Re is a rare earth element));
In the melt for crystallizing at least (Bi, Re) ₃ Fe ₅ O ₁₂ melted in the crucible,
After contacting the seed crystal,
While pulling up the seed crystal to grow (Bi, Re) ₃ Fe ₅ O ₁₂ single crystal,
A method for growing a garnet-type single crystal, characterized in that a raw material having the same composition as the pulled single crystal is supplied to the melt. The melt is melted in a crucible, the crucible is an external crucible,
An internal crucible provided in the external crucible;
6. The method for growing a garnet-type single crystal according to claim 5, further comprising a flow passage for circulating the melt in the outer crucible and the inner crucible. The seed _{crystal, (Bi, Re) 3 Fe} 5 O 12 single crystal and / or _{(Gd, Ca) 3 (Ga} , Mg, Zr) 5 O 12 claim 5 or characterized in that it is a single crystal A method for growing a garnet-type single crystal according to claim 6. In the method for growing a garnet-type single crystal according to claim 1,
X is (Bi, Tb),
In the melt for crystallizing at least (Bi, Tb) ₃ Fe ₅ O ₁₂ melted in the crucible,
After contacting the seed crystal,
While pulling up the seed crystal and growing a (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal,
A method for growing a garnet-type single crystal, characterized in that a raw material having the same composition as the pulled single crystal is supplied to the melt. The melt is melted in a crucible, the crucible is an external crucible,
An internal crucible provided in the external crucible;
9. The method for growing a garnet-type single crystal according to claim 8, further comprising a flow passage for circulating the melt in the external crucible and the internal crucible. The said seed crystal is a (Bi, Tb) ₃ Fe ₅ O ₁₂ single crystal and / or a (Gd, Ca) ₃ (Ga, Mg, Zr) ₅ O ₁₂ single crystal, A method for growing a garnet-type single crystal according to claim 9.

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